_system_path.py 文件源码

def remove_from_system_path(pathname, allusers=True, path_env_var='PATH'):
    """Removes all entries from the path which match the value in 'pathname'

       You must call broadcast_environment_settings_change() after you are finished
       manipulating the environment with this and other functions.

       For example,
         # Remove Anaconda from PATH
         remove_from_system_path(r'C:\Anaconda')
         broadcast_environment_settings_change()
    """
    pathname = path.normcase(path.normpath(pathname))

    envkeys = [(reg.HKEY_CURRENT_USER, r'Environment')]
    if allusers:
        envkeys.append((reg.HKEY_LOCAL_MACHINE,
            r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment'))
    for root, keyname in envkeys:
        key = reg.OpenKey(root, keyname, 0,
                reg.KEY_QUERY_VALUE|reg.KEY_SET_VALUE)
        reg_value = None
        try:
            reg_value = reg.QueryValueEx(key, path_env_var)
        except WindowsError:
            # This will happen if we're a non-admin install and the user has
            # no PATH variable.
            reg.CloseKey(key)
            continue

        try:
            any_change = False
            results = []
            for v in reg_value[0].split(os.pathsep):
                vexp = sz_expand(v, reg_value[1])
                # Check if the expanded path matches the
                # requested path in a normalized way
                if path.normcase(path.normpath(vexp)) == pathname:
                    any_change = True
                else:
                    # Append the original unexpanded version to the results
                    results.append(v)

            modified_path = os.pathsep.join(results)
            if any_change:
                reg.SetValueEx(key, path_env_var, 0, reg_value[1], modified_path)
        except:
            # If there's an error (e.g. when there is no PATH for the current
            # user), continue on to try the next root/keyname pair
            reg.CloseKey(key)